single authentication

Do you currently use F5 LTM (not APM) to authenticate user sessions for some application?

If you have APM as an option I would recommend looking into provisioning and using APM as it would be a lot easier than trying to do anything in LTM.

If you do need something in LTM it would be an iRule, or even a set of iRules, but would need to know what you are trying to do in more detail before we could help.